Audi?s diesel monster

Behind the wheel of the diesel that drives like a big V8.

Audi?s diesel monster

As the speedo needle nudges an indicated 270km/h it’s hard not to be impressed by Audi’s latest creation.

From low speed, the engine pulls strongly and doesn’t stop pulling until you’re way beyond any speed limit in Australia.

This new engine will be the hero of the A6 sedan and A7 Sportback ranges when it arrives in the first quarter of next year.

It produces a mighty 230kW of power and a whopping 650Nm of torque - impressive figures whichever way you look at it.

But instead of relying on a big capacity or high-revving petrol-fuelled V8 as in years gone by, this engine is a diesel; a 3.0-litre V6 twin-turbo diesel to be precise.

In the German firm’s continuing campaign to make diesel “sexy” the 3.0 TDI bi-turbo (to give it its official name) will be the premium engine for both the A6 and A7 line ups; sitting just below the purely performance orientated S6 and S7 models.

If you want an example of just how far diesel engines have come in the last decade, look no further than this. It sounds good, pulls hard no matter how many revs you give it and is still easy on the fuel.

The new engine outguns the current 3.0 TDI V6, found in a variety of Audi’s including the A6 and A7, by a considerable margin.

It has an additional 50kW of power and torque is up a by 150Nm. Just as impressively, it produces all that extra grunt with only a minor increase in fuel consumption and CO2 emissions compared to the single turbo 3.0 TDI.

Compared to the 3.0 TDI’s 6.0-litre per 100km fuel figure, the bi-turbo uses only 6.4L/100km and emissions increase from 158g/km to 169g/km.

The two turbos (one small, one large) work separately at revs below 2500rpm, then in partnership to 3500rpm. At 4000rpm the larger turbo takes over completely.

Power is fed to all four wheels via Audi’s Quattro all-wheel drive system coupled to an eight-speed automatic transmission.

Having eight ratios has allowed Audi to stack them shorter at the bottom end for better acceleration, and then make them longer in the higher gears for low-rev cruising at freeway speeds.

After spending a day behind the wheel taking in a variety of German roads, including long stretches of unrestricted autobahns, it’s hard not to be impressed by the bi-turbo.

Its linear power delivery and effortless pulling power put plenty of bigger capacity, petrol performance engines to shame.

While there is still space for the S7 and its twin-turbo 4.0-litre V8, for most people, and certainly in Australian conditions, the A7 3.0 TDI bi-turbo has more than enough performance to satisfy even enthusiast drivers.

The driving dynamics of the rest of the car remain unchanged from the other A7 Sportbacks. It is a comfortable cruiser, but not what you would call an pure sports sedan. It feels well balanced and stable at speed and composed through the bends; but you are constantly reminded of its bulk when you try to change directions or slow down in a hurry.

The steering could still provide the driver with more feedback, but it is light around town which is nice for parking.

So it all sounds too good to be true, right?

Well there is a catch, and it’s a big one: the price. Audi hasn’t confirmed final specification and pricing but it is tipped to add approximately $15,000 to the $142,700 (plus on-road costs) of the current 3.0 TDI A7.

Audi Australia hasn't confirmed final specifications but the it is expected the biturbo will also add more standadrd equipment to help position the car as a range-topper; and justify the hefty price increase.

Certainly the engine warrants your consideration if you are looking for a sporty car with plenty of poke, even if you are a die-hard petrolhead.

Diesel may still have some stigmas attached to it from its working class roots but if Audi and other car makers continue to produce engines like this, it will soon win the hearts of performance lovers.